WO2016075508A1

WO2016075508A1 - Method for producing an oil layer by controlling the load cycle

Info

Publication number: WO2016075508A1
Application number: PCT/IB2014/065927
Authority: WO
Inventors: César RODRIGUEZ; Rómulo SOTO; Jesús BETANCOURT
Original assignee: Summit Energy Sas
Priority date: 2014-11-10
Filing date: 2014-11-10
Publication date: 2016-05-19

Abstract

The present invention relates to a method for working a type of oil well, which allows the profitable operation of such oil wells which would otherwise remain closed or abandoned, reducing the productive life cycle thereof. In particular, the present invention is applicable to wells which produce in reservoirs that have developed the phenomenon known as water coning, due to the characteristics of the wells. Thus, the invention is the application to this type of well of a process called oil layer production by controlling the load cycle, which is based on a series of linked activities that includes a selective non-reactive stimulation, only in the oil zone, by injecting a mixture of solvents and surfactants, to considerably reduce interfacial water-oil tension at reservoir level, so that the top of the water cone can be truncated and the production of crude oil increases once the well is exploited. The purpose of the present invention is to extend the productive life of the wells to which the method is applied.

Description

OIL COAT PRODUCTION PROCESS

CONTROLLING THE LOAD CYCLE

D E S C R I P C I O N

OBJECT OF THE INVENTION

The present invention relates to a process for working a type of oil well that allows its profitable operation that would otherwise remain closed or abandoned, shortening its productive life cycle. Particularly, the present invention is applicable to wells that produce in deposits that due to their characteristics have developed the phenomenon known as water conification. The invention is then the application to this universe of wells of a process called oil layer production by controlling the loading cycle that lies in a series of chained activities that includes selective and non-reactive stimulation, only in the oil zone, injecting a mixture of solvents plus surfactants, to drastically reduce the water-oil interfacial tension at the reservoir level, so that the water cone is truncated at its cusp and the production of crude oil is magnified once the well has been subjected to production. The object and purpose of the present invention is to extend the productive life of the wells to which the process is applied.

FIELD OF THE INVENTION

The present invention has application within the area of oil exploitation in finished wells. Particularly, the present invention relates to the production of the oil layer by controlling the loading cycle by applying a method consisting of a series of chained and successive actions that include selective and non-reactive stimulation, only in the oil zone. According to the present invention, the technology is oriented to the oil exploitation in finished wells as well as to facilitate the hauling of the fines that are accumulated in the area near the well since the stimulation fluid has the property of keeping them in suspension and driving them out. of the porous space when production is restarted.

BACKGROUND OF THE INVENTION

The proposed initiative is aimed at the universe of wells that are completed in Deposits characterized by having high bottom pressure, very active hydraulic thrust as a production mechanism, high vertical permeabilities and unfavorable mobility.

Deposits with these characteristics merit to make their exploitation profitable, that the production rates exceed the critical regime, so that the water-oil interface becomes unstable. Similarly, within the water-oil balance it is typical for these types of wells to appear early, a conification of the water-oil contact. In this way the water blocks the migration of crude oil, leaving volumes of crude oil without being drained inside the reservoir.

This reality, causes that the extracted fluids, have increasing volumes of water that make this process economically unfeasible, since the income from the sale of the associated low volumes of crude oil, does not cover the total of the operation and as a consequence determines the closure of these wells. Within the productive balance, the extraction of water cannot be significantly superior to the extraction of oil, since if so, the well is classified as unprofitable.

Therefore, the present invention provides a new form of oil extraction.

DESCRIPTION OF THE INVENTION

The present invention relates to a process for the production of an oil layer by controlling the loading cycle by applying a process consisting of a series of chained and successive actions that include selective and non-reactive stimulation, only in the oil zone, injecting a mixture of solvents plus surfactants and thus extend the productive life of a well that has been finished.

DESCRIPTION OF THE FIGURES.

To further clarify the invention and its advantages compared to the known art, the possible forms of illustrative and non-limiting embodiments of the application of said principles are described below with the help of the attached drawings.

Figure 1 illustrates a schematic view of the reservoir where it has been determined that the water-oil contact forms a cone whose vertex is determined by the holes of the cannon made to the well during its completion and where the process of the present is applicable invention. PREFERRED EMBODIMENT OF THE INVENTION.

The present invention relates to a process for the production of an oil layer by controlling the loading cycle by applying a process consisting of a series of chained and successive actions that include selective and non-reactive stimulation, only in the oil zone, injecting a mixture of solvents plus surfactants, to drastically reduce the interfacial water-oil tension, in such a way that the water cone is truncated on its cusp and the production of crude oil is magnified once the well has been subjected to production.

The present invention is directed to the universe of wells that are completed in Deposits characterized by having:

-High background pressure;

-Highly active hydraulic thrust as a production mechanism; -High vertical permeabilities; Y,

- Unfavorable reason for mobility.

For the profitable exploitation of these deposits, the production rates exceed the critical regime, so the water-oil interface becomes unstable, so it is typical that the conification of the water-oil contact appears early. Water blocks the migration of crude oil, leaving volumes of crude oil without being drained.

This reality causes the extracted fluids to have increasing volumes of water that make this process economically unfeasible, since the income from the sale of the associated low volumes of crude oil does not cover the total operation and as a consequence determines the closure of these wells. For this purpose, the operation of these wells is provided by the present invention by applying the oil layer production by controlling the loading cycle. From this, it is possible to produce approximately the same amount of oil, but with low water cuts.

Among other benefits involved in this initiative are the efficient drainage of asset reserves, which are already contacted but "left behind" because their exploitation is uneconomic. Another benefit is the due reduction of OPEX (Operational Costs), as it has lower volumes of water produced that optimize the cost of lifting and treatment (lower electrical and chemical consumption, reduction of maintenance of parts and equipment). It also involves the reduction of disbursement for subsoil interventions to wells (there is no fluid stroke, or buoyancy) as well as CAPEX (Capital invested) is optimized for the use of smaller equipment and facilities because lower flows are managed ( reduction of subsoil pumps, collection systems, flow stations).

For this, the present invention consists in determining the layer of oil that accumulates under static conditions in the well and extracting it with mechanical subsoil pumping. For this, the percentage (%) of filling of the pump is controlled and combines programmed operating cycles, stops and starts to minimize water production.

The layer of oil that is generated is determined from a hydrostatic balance of energy based on the static pressure of the reservoir, calculated at the midpoint of the perforations, and the static level of the fluid inside the well, using the formula: Where:

Ps = Static reservoir pressure (measured)

I = Petroleum Hydrostatic Gradient

Yw = Water hydrostatic gradient

ho = Oil height

hw = Water height

The hydrostatic oil gradient is calculated:

I = ¹⁴¹ - ⁵ * 0.433 ^

131.5 + ° CC API

The hydrostatic water gradient is calculated:

With these equations an iterative process is followed, giving different values to the heights of water and oil until the static pressure of the reservoir is reproduced.

Once the height of the oil and the casing diameter (Casing) with which the well is completed is known, the equivalent cumulative volume is derived, using the formula: The volume of oil to be extracted is calculated based on the proposed depth of the subsoil pump and its operating regime, regulated on the surface by an intelligent variator that controls the percentage (%) of filling of the pump from the dynamics charts of the pump that are derived by torque and motor speed measurements.

According to the present invention, the pumping action empties a section of oil in the annular space. Over time, the pump shows a dynamic letter with a pump condition operating in a vacuum (pump off), or that produces fluid production on the surface with a maximum water cut of 50%. The drive automatically orders the system to stop as long as either of the two conditions described above is met. Using the reservoir pressure data and static levels, the time in which the operation must be restarted is determined, an action that is programmed by the intelligent inverter.

Based on Figure 1, it is based on the knowledge that the flow regimes with which well 1 is exploited, which includes the water zone 2 and the oil zone 3 that has determined that the water-oil contact 4 forms a cone 5 whose vertex 6 is determined by the perforations 7 in the Casing, which prevents the communication of the interior of the well with the zone of greater saturation 8 of hydrocarbons.

The process of the present invention, then successively comprises the following steps: i. A first step of extraction of the completion with the current artificial lifting system with which the well has been produced so far;

I. A second step consists of lowering with a pipe carrying a gasket that allows, by means of its settlement, to isolate the upper section of the interval that includes the perforations 7 corresponding to the oil zone 8 that is to be stimulated; i. A third step is the non-reactive matrix stimulation in the upper area of the reservoir, already isolated with the packing, by pumping from the surface the stimulation chemicals in the matrix regime;

iv. A fourth step is to extract the pipe with the gasket, leaving the entire originally open interval exposed to production;

v. A fifth step as illustrated in Figure 2, comprising recompleting the well with mechanical pumping by placing the suction of the subsoil pump within the range of the oil layer 9 formed in the column of water-oil fluids inside well 1 . At this time the cone 5 'and the cusp 6' has already been reduced and therefore they have allowed said interval of the oil zone 8 to be in a flow line with the perforations 7 in the Casing;

saw. A sixth step is to restart the production of the well with the new method of artificial lifting (mechanical pumping).

With matrix stimulation by the third step of the present invention, the damage factor is reduced and the minimum tension between the oil and water phases is guaranteed and thus the conification effect is reduced.

The invention is aimed at breaking the architecture that the fluids that have formed around the well. To do this, hereby invention, selective-non-reactive stimulation is carried out, only in the oil zone, by injecting a chemical formed by a mixture of solvents plus surfactants, to drastically reduce the water-oil interfacial tension, so that the cone is truncated of water on its cusp and the production of crude oil is magnified once the well has been subjected to production.

This treatment also has the property of facilitating the hauling of fines that are accumulated in the area near the well since the stimulation fluid has the property of keeping them in suspension and of driving them out of the porous space when production is restarted.

Only some preferred embodiments of the invention have been illustrated by way of example. In this regard, it will be appreciated that the process for the production of the oil layer, as well as the configurations, can be chosen from a plurality of alternatives without departing from the spirit of the invention according to the following claims.

Claims

Process for oil layer production CHARACTERIZED BECAUSE it comprises:

(i). A first step of extraction of the completion with the current artificial lifting system with which the well has been produced so far;

(¡I). A second step consists of lowering with a pipe leading to a gasket that allows, by means of its settlement, to isolate the upper section of the interval that includes the perforations (7) corresponding to the oil zone (8) to be stimulated;

(iii). A third step is the non-reactive matrix stimulation in the upper area of the reservoir, already isolated with the packing, by pumping from the surface the stimulation chemicals in the matrix regime;

(iv). A fourth step is to extract the pipe with the gasket, leaving the entire originally open interval exposed to production;

(v). A fifth step that involves recompleting the well with mechanical pumping by placing the suction of the subsoil pump within the range of the oil zone (8) formed in the column of water-oil fluids inside the well (1). At this time the cone (5 ') and the cusp (6') has already been reduced so that the interval of the oil zone (8) is in a flow line with the perforations (7) in the Coater; Y,

(saw) . A sixth step is to restart the production of the well with the new method of artificial lifting (mechanical pumping).